Australian diesel pump prices could reach $A2 ($NZ2.57) a litre by next year, a fuel monitoring company says.

It also predicts a "continual gradual upward movement" in the price of unleaded petrol during the next two months.

Diesel has hit $A1.80 a litre in some capital cities while unleaded petrol pushed through the $A1.60 mark yesterday on the back of rising world oil prices.
Increased demand from China is contributing to the cost of diesel, Fueltrac managing director Chris Cable says.

"They're actually starting to stockpile diesel, with a view to building efforts in that part of the world," he told ABC Radio.

"I understand that they're also trying to ensure that there are no power disruptions around the Olympic Games [in China in August]."

Mr Cable has warned motorists that fuel prices are still on the way up.
"The general consensus around our office is that there will be a continual gradual upward movement in the price of both unleaded and diesel over at least the next couple of months," he said.

"$A2 a litre I would hope doesn't materialise.
"Given that we've already reached $A1.80 and even higher for diesel then ... I wouldn't have said this six months ago, but absolutely definitely possible, for at least diesel (to hit $A2 a litre)."

Separately, RACV manager of government and corporate relations David Cumming says Melbourne motorists should brace for prices at the pump as high as $A1.63 a litre next week and warned the worst was yet to come.

"Unfortunately we haven't peaked yet at all, some will attempt to go $A162.9, some will attempt to go at a higher price next week," Mr Cumming told AAP.
"Just prepare yourself for higher prices, that's all I can say."